In a communication arrangement, a communication device communicates with a further communication device. There may be more than two communication devices in an area or more than two persons in an area. Thus, methods have to be used to achieve a secure communication. For example, a communication device may be coupled to an electrical door lock. A person having a further communication device with an authentication code may be near the door. For security reasons, the door may not be opened in the case that a further person enters the space between the person and the door.
There is a desire to provide a communication device and a method for communication with increased security.